#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Software: PyCharm
# @Version : Python-
# @Author  : Shengji He
# @Email   : hsjbit@163.com
# @File    : MatrixCellDistanceOrder.py
# @Time    : 2020/11/17 10:59
# @Description:
from typing import List


class Solution:
    def allCellsDistOrder(self, R: int, C: int, r0: int, c0: int) -> List[List[int]]:
        """
        We are given a matrix with R rows and C columns has cells with integer coordinates(r, c),
        where 0 <= r < R and 0 <= c < C.

        Additionally, we are given a cell in that matrix with coordinates(r0, c0).

        Return the coordinates ofall cells in the matrix, sorted by their distance from (r0, c0)from smallest distance
        to largest distance. Here,the distance between two cells (r1, c1) and (r2, c2) is the Manhattan distance,
        |r1 - r2| + |c1 - c2|. (You may return the answer in any order that satisfies this condition.)

        Example 1:
            Input: R = 1, C = 2, r0 = 0, c0 = 0
            Output: [[0,0],[0,1]]
            Explanation: The distances from (r0, c0) to other cells are: [0,1]
        Example 2:
            Input: R = 2, C = 2, r0 = 0, c0 = 1
            Output: [[0,1],[0,0],[1,1],[1,0]]
            Explanation: The distances from (r0, c0) to other cells are: [0,1,1,2]
            The answer [[0,1],[1,1],[0,0],[1,0]] would also be accepted as correct.
        Example 3:
            Input: R = 2, C = 3, r0 = 1, c0 = 2
            Output: [[1,2],[0,2],[1,1],[0,1],[1,0],[0,0]]
            Explanation: The distances from (r0, c0) to other cells are: [0,1,1,2,2,3]
            There are other answers that would also be accepted as correct,
            such as [[1,2],[1,1],[0,2],[1,0],[0,1],[0,0]].

        Note:
            - 1 <= R <= 100
            - 1 <= C <= 100
            - 0 <= r0 < R
            - 0 <= c0 < C

        :param R:
        :param C:
        :param r0:
        :param c0:
        :return:
        """
        ans = [[j, i] for i in range(C) for j in range(R)]
        ans.sort(key=lambda x: abs(x[0] - r0) + abs(x[1] - c0))
        return ans

    def allCellsDistOrder2(self, R: int, C: int, r0: int, c0: int) -> List[List[int]]:
        dirs = [(1, 1), (1, -1), (-1, -1), (-1, 1)]
        maxDist = max(r0, R - 1 - r0) + max((c0, C - 1 - c0))

        row, col = r0, c0
        ret = [[row, col]]

        for dist in range(1, maxDist + 1):
            row -= 1
            for i, (dr, dc) in enumerate(dirs):
                while (i % 2 == 0 and row != r0) or (i % 2 != 0 and col != c0):
                    if 0 <= row < R and 0 <= col < C:
                        ret.append([row, col])
                    row += dr
                    col += dc
        return ret


if __name__ == '__main__':
    S = Solution()
    # R = 2
    # C = 2
    # r0 = 0
    # c0 = 1
    R = 6
    C = 4
    r0 = 3
    c0 = 2
    # print(S.allCellsDistOrder(R, C, r0, c0))
    print(S.allCellsDistOrder2(R, C, r0, c0))
    print('done')
